1. Field of the Invention
This invention generally relates to a bicycle front derailleur. More specifically, the present invention relates to a bicycle front derailleur that smoothly and reliably shifts a bicycle chain between the front sprockets of the drive train, and which aggressively shifts the bicycle chain to a larger front sprocket from a smaller front sprocket.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component or part of the bicycle that has been extensively redesigned over the years is the front derailleur. A front derailleur is typically mounted onto the bicycle frame adjacent to the front sprockets to shift the chain laterally between the front sprockets. Many bicycles have two or three front sprockets.
Generally, a front derailleur includes a fixed member non-movably secured to a bicycle frame, and a movable member supported to be movable relative to the fixed member. Typically, the fixed member is a tubular clamping member that is secured to the seat tube. Alternatively, the fixed member is sometimes coupled to the bottom bracket or coupled to a brazed-on mounting structure of the frame. In any case, the movable member typically has a chain guide with a pair of cage plates for contacting and moving a chain laterally between the front sprockets. The movable member is usually biased in a given direction relative to the fixed member by a spring. The movable member is usually moved relative to the fixed member by pulling and/or releasing a shift control cable that is coupled to the front derailleur. The movable member and the fixed member usually are interconnected through a plurality of pivotal links (i.e. a linkage assembly).
One problem with typical front derailleurs is that the chain is not always shifted from the smaller sprocket to the larger sprocket(s) as quickly (aggressively), smoothly and reliably as desired by some riders. Thus, undesirable audible clicking sounds can sometimes occur. Moreover, optimum power transfer from the rider to the bicycle might not be achieved during a front up shift (from smaller sprocket to larger sprocket) of the bicycle chain.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle front derailleur that overcomes the above mentioned problems in the prior art. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.